This invention relates to the consolidation of aggregate material. In another aspect, it relates to consolidating or stabilizing superficial mineral aggregate, such as soil or sand or decorative rocks, to form a consolidated structure.
The prior art discloses the use of a host of materials and techniques for the treatment of mineral aggregate to overcome problems arising from the inherent nature of the unconsolidated aggregate. The purpose of some of such techniques has been to form load-bearing structures. In other areas polymers have been used to seal subterranean formations penetrated by well bores (e.g. see U.S. Pat. Nos. 2,867,278; 3,181,611; and 3,181,612).
Hydrophilic or water-soluble urethane prepolymers have also been successfully used in a variety of soil stabilizing techniques. For example, see U.S. Pat. No. 3,719,050; assignee's copending application Ser. No. 100,378, filed Dec. 21, 1970, now U.S. Pat. No. 3,805,531; and assignee's copending application Ser. No. 190,358, filed Oct. 18, 1971, now U.S. Pat. No. 3,805,532. Although such systems are quite useful, the stabilized aggregate does have reduced integrity when saturated with water, especially over a long period of time.
Although U.S. Pat. No. 3,367,892 describes the use of a polyurethane for stabilizing soil, the systems described there are two-part and are reacted so as to cause foaming thereof. The resulting polymer is highly foamed and does not provide an aesthetically pleasing surface. Furthermore, the resulting stabilized soil is water-impermeable.
In U.S. Pat. No. 3,651,649 there is described a method for stabilizing soil using a water-based emulsion of vinyl ester resin. The resulting stabilized soil is said to be liquid impermeable, and the polymer encapsulates or traps water droplets therein.